What is Random Access Memory (RAM)? ||Random Access Memory (RAM) || TYPES OF RAM

Ram

Random access memory, in short, is a data type of computer. Random data can be accessed in any order, which is called random access memory. The random word here implies - any data (depends on its location) can be retrieved at exactly the same time. In protective eyes, modern decay is not random access memory (as it can read data). At the same time, random access memory of various types of serum, ROM, OTP and nor flash. RAM is called volatile memory because the stored data does not end there. Some other non-volatile memory (which do not wipe data even after the power has gone), which are RAM in a protective sense, ROM, a kind of flash memory called no-flash. The first Ram module came on the market, which was produced in 1951 and 1960's and was sold in the early 1970's. However, other memory devices (magnetic tapes, discs) can definitely enter and use them in their stored memory for while.

TYPE OF RAM -

There are two types of Ram

1. DRAM (Dynamic Random Access Memory)
2. SRAM (Static Random Access Memory)

Operation:

 Similar to a microprocessor, a memory chip is an integrated circuit (IC) made of millions of transistors and capacitors. In the most common form of computer memory, dynamic random access memory (DRAM), a transistor and a capacitor are paired to create a memory cell, which represents a single bit of data. The capacitor holds the bit of information - a 0 or a 1. The transistor acts as a switch that lets the control circuitry on the memory chip read the capacitor or change its state. A capacitor is like a small bucket that is able to store electrons. To store a 1 in the memory cell, the bucket is filled with electrons. To store a 0, it is emptied. The problem with the capacitor's bucket is that it has a leak. In a matter of a few milliseconds a full bucket becomes empty. Therefore, for dynamic memory to work, either the CPU or the memory controller has to come along and recharge all of the capacitors holding a 1 before they discharge. The capacitors must to be energized every 15ms or so (hundreds of times per second) to maintain their charge. To do this, the memory controller reads the memory and then writes it right back. This is refresh operation happens automatically and is how dynamic RAM got its name. Dynamic RAM has to be dynamically refreshed all of the time or it forgets what it is holding. The downside of all of this refreshing compared to SRAM is that it takes time and slows down the memory

Memory cells are etched onto a silicon wafer in an array of columns (bitlines) and rows (wordlines). The intersection of a bitline and a wordline constitutes the address of the memory cell. DRAM works by sending a charge (an electrical signal called a strobe) through the appropriate column (CAS) to activate the transistor at each bit in the column. When writing, the row lines contain the state the capacitor should take on. When reading, the sense-amplifier determines the level of charge in the capacitor. If it is more than 50 percent, it reads it as a 1; otherwise it reads it as a 0. The counter tracks the refresh sequence based on which rows have been accessed in what order. The length of time necessary to do all this is so short that it is expressed in nanoseconds (billionths of a second). A memory chip rating of 70ns means that it takes 70 nanoseconds to completely read and recharge each cell. Memory cells alone would be worthless without some way to get information in and out of them. So the memory cells have a whole support infrastructure of other specialized circuits. These circuits perform functions such as: 

•Identifying each row and column (row address select and column address select) 

•Keeping track of the refresh sequence (counter) 

•Reading and restoring the signal from a cell (sense amplifier) 

•Telling a cell whether it should take a charge or not (write enable) Other functions of the memory controller include a series of tasks that include identifying the type, speed and amount of memory and checking for errors. 

1. When you open an application such as Excel, it is loaded into RAM. To conserve RAM usage, many applications load only the essential parts of the program initially and then load other pieces as needed. 

2. After an application is loaded, any files that are opened for use in that application are loaded into RAM.

 3. When you save a file and close the application, the file is written to the specified storage device, and then it and the application are purged from RAM.

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